Copper base alloy



July 28, 1970 c. 0. M LAIN COPPER BASE ALLOY 2 Sheets-Sheet 1 Filed June 26, 1967 ALLOY- 3 E ALLOV- 5 y WWMEQQYI k .3 QQQSXUQQ AS RECEIVED TEMPLRA TURE -F FIG-l INVENTORZ CHARLES llMcLA/N BY 2M ATTORNEY July 28, 1970 Filed June 26. 1967 S TRENGTH PSI.

2 SheetsShe et 2 TENS/LE STRENGTH 4B a RECAESIVED 600 700 TEMPERATURE-OF 2 INVENTOR: CHARLES D.Mc LA/N ATTORNEY United States Patent 3,522,038 COPPER BASE ALLOY Charles D. McLain, Alton, Ill., assignor to Olin Corporation, a corporation of Virginia Filed June 26, 1967, Ser. No. 648,660

Int. Cl. C22c 9/00, 9/10 US. Cl. 75-153 7 Claims ABSTRACT OF THE DISCLOSURE As is well known in the art, copper is an excellent conductor of electricity. Numerous alloying additions have been proposed in order to increase the strength of copper.

111 50 doing, the electrical conductivity of the copper is v markedly reduced.

-It is, therefore, highly desirable to provide a copper base alloy characterized by high conductivity and increased strength.

Accordingly, it is a principal object of the present invention to provide a copper base alloy characterized by high electrical conductivity and high strength properties.

It is a further object of the present invention to provide a copper base alloy with annealed physical properties which do not have a wide variation.

It is a further object of the present invention to provide a copper base alloy having the ability to attain various strength levels as a result of different annealing treatments, even when small amounts of impurities are present.

It is a further object of the present invention to provide an improved copper base alloy having a combination of high strength, high conductivity, and other excellent physical properties.

It is an additional object of the present invention to provide a copper base alloy which is inexpensive and wherein theexcellent physical properties are easily obtainable.

Further objects and advantages of the present invention will appear from the ensuing specification.

In accordance with the present invention it has been found that an improved copper base alloy is provided which effectively achieves the foregoing objects and advantages. The alloy of the present invention comprises a copper base alloy consisting essentially of from 1.5 to 3.5% iron, 0.02 to 0.21% silicon and the balance essentially copper. In addition, the copper base alloy of the present invention effectively utilizes additional additives such as phosphorus in an amount from 0.01 to 0.15%, preferably from 0.01 to 0.10%, and zinc in an amount from 0.03 to 0.20%, preferably from 0.03 to 0.15%, and mixtures thereof. Throughout the ensuing specification all percentages are percentages by weight.

In accordance with the present invention, it has been surprisingly found that the foregoing alloys are characterized by numerous unexpected and surprising advantages. For example, the alloys of the present invention have an unexpected improvement in electrical conductivity. Namely, there is readily obtained an IACS electrical conductivity in excess of 70% IACS, and a range of 75 to 81% IACS is readily attained. Furthermore, the alloys of the present invention have excellent annealing characteristics, with the ability to attain various strength levels as a result of different annealing treatments. In addition,

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the alloys of the present invention attain high rolled temper strength levels. Still further the high electrical conductivity of the alloys of the present invention is coupled with excellent annealed tensile strength properties of approximately 65,000 p.s.i. and higher. The strength and physical properties of the alloys of the present invention are not significantly variable if small amounts of impurities are present. Still further the alloys of the present invention resist softening during soldering at 700 to 800 F. In addition to the foregoing, the alloys of the present invention are inexpensive and their excellent physical properties easily obtainable.

The composition of the alloys of the present invention is as stated heretofore. The preferred iron content is from 1.7 to 3.0%, with an optimum from 1.8 to 2.9% and the preferred silicon content is from 0.03 to 0.20% with an optimum range being from 0.10 to 0.17%.

In view of the high and in fact surprising physical properties of the alloys of the present invention, the percentage ranges of the alloying ingredients are important.

In addition to the foregoing, small amounts of additional alloying ingredients may be, of course, included in order to achieve particularly desirable results, for example, aluminum in an amount up to 0.07% and manganese in an amount up to 0.08%. Also, small amounts of impurities may, of course, be tolerated.

The alloys of the present invention attain improvement over conventional alloys in a wide range of processing. Naturally, however, particular processing will result in variation in properties.

The manner of casting the material is not particularly critical, with conventional casting methods for these types of alloys being readily utilizable, it being noted-that higher temperatures should be used in order to solutionize the iron. It is preferred to cast the alloy into billets of conventional size, subjecting them to hot working, as by rolling in the conventional size.

After casting the alloy should be hot rolled at an elevated temperature, i.e., from 800 to 1050 C., with a temperature ofabout 950 C. being preferred. The alloy should then be cold rolled to gage, with intermediate anneals, with cold reduction in excess of 50% between anneals being preferred. Annealing temperatures of from 400 to 600 C. are preferred, with annealing time at temperature preferably being a minimum of two (2) hours. Longer times may be utilized, if desired, for improved electrical conductivity. Continuous strand annealing of strip or mill products will achieve the same high level of physical properties as with Bell annealing, but will not achieve as high a level of electrical conductivity. Therefore, for development of both high annealed strength and electrical conductivity, final annealing and preferably in process annealing must be in batches with conventional furnace cooling, such as Bell annealing.

Detailed processing and preferred processing parameters consonant with the foregoing are found in co-pending application Ser. No. 648,742 for Process for Treating Copper Base Alloy, filed of even date herewith, by C. D. McLain.

The present invention will be more readily understandable from a consideration of the following illustrative examples.

EXAMPLE I Alloys were prepared in the following manner. High purity copper and high purity iron were melted together in a low frequency, slot type induction furnace under a charcoal cover at approximately 1200 C. About 10% of the copper charge was held back and the melt was slightly overheated to about 1300 C. in order to put the iron into solution. High purity alloying additions were added when the molten mass was at about 1300 C. The and tensile strength. The results are shown in FIGS. 1 balance of the copper was added and the melt brought and 2. FIG. 1 is a curve of Rockwell 1ST hardness to the pouring temperature of about 1200 C. The melt versus temperature and FIG. 2 is a curve of strength was then poured into a water-cooled ingot mold of versus temperature. In FIGS. 1 and 2, the solid lines 28%" x x 96 at a pouring rate of 21.3" per minute. represent the data after 3 minutes immersion in the salt The alloys thus prepared had the following composition. 5 bath and the dashed lines represent the data after 4 TABLE 1 Iron, Phosphorus, Silicon, Zinc, Alloy percent percent percent percent Copper 2.3 0.021 0.13 0.08 Essentially balance. 23 0. 03 Do.

EXAMPLE II minutes immersion in the salt bath. There was no change in electrical conductivity of any of the alloys.

These graphs vividly demonstrate that alloy 3, the alloy of the present invention, is markedly and surprisingly superior to conventional alloys 4 and 5.

Alloys 1 and 2 prepared in Example I were processed as follows. The alloys were hot rolled at from 900 to 940 0., followed by a water spray quench to room temperature. The materials were then cold rolled to 0.100", bell annealed at 480600 C. (1 to 4 hours at EXAMPLE IV temperature), cold rolled to 0.050", bell annealed at 460 to 480 C. (1 to 3 hours at temperature), and cold rolled In this example three alloys were prepared in a manto 0.025" gage and bell annealed at 440 to 480 C. (1 ner after Example I, wherein the alloys had the followto 3 hours at temperature). g COmPOSItIOHSt TABLE IV Phosphorus, Iron, Silicon Zinc, Alloy percent percent percent percent Copper 6 0.021 2.3 0.13 0.08 Essentially balance. 7 2.4 0.14 Do. 8 0.025 2.4 D0,

The alloys were then tested for physical properties, The alloys were processed in the following manner. with the results being shown in the following table. The five 1nch thick slabs were hot rolled at 925 C. to TABLE H 0.350", milled to 0.300", cold rolled to 0.100", annealed Yi m T 1 E t i 1 for two hours at 490 C., cold rolled to 0.050, annealed e ensie I at 440 C. for two hours and cold rolled to 0.025 and h t th l t o d t t Alloy if if s $5.11 E 530821: itta??? IIXICYS annealed for two hours at 440 C. 1 26 900 53 400 27 812 After each anneal the tensile strength and electrical 21:11:11-: 231100 501100 27.5 73.5 conductivity of each sample was determined and the results are shown in the following table.

TABLE V First Annoal Second Anneal Third Anneal Tensile Electrical Tensile Electrical Tensile Electrical Strength, Conductivity, Strength, Conductivity, Strength, Conductivity, Alloy p.s.i. percent IACS p.s.i. percent IACS p.s.i. percent IACS foregoing flemonstfates alloy alloy 'E This invention may be embodied in other forms or present invention, achieves hlgher electrical conductivlty carried out n other Ways without departing from the thal; g tg i 1 and also develops greater spirit or essential characteristics thereof. The present emma 6 streng eve bodiment is therefore to be considered as in all respects EXAMPLE III illustrative and not restrictive, the scope of the invention being indicated by the appended claims, and all changes which come within the meaning and range of equivalency are intended to be embraced therein.

In this example three alloys were prepared in a manner after Example I, wherein the alloys had the following com-positions:

TABLE 111 Iron Silicon, Phosphorus, Silver, Oxygen, Alloy percent percent percent percent percent Copper 3 2.4 0.12 Essentially balance. 4 2.4 0.02 Do. 5 0.06 0.04 Do.

The alloys were then processed in a manner after Exam- What is claimed is: ple II, with an additional cold rolling to increase strength 1. A copper base alloy consisting essentially of from level, and then tested for softening temperature in the 1.5 to 3.5% iron, from 0.02 to 0.21% silicon, at least following manner. The alloys were immersed in a salt one of the elements P and Zn, P being present in an bath at elevated temperatures from 600 to 800 F. for amount of 0.01 to 0.15% and Zn being present in an periods of time of 3 and 4 minutes. The samples were amount of 0.03 to 0.2% Zn, balance copper, said alloy then tested for Rockwell 1ST hardness, yield strength having an IACS electrical conductivity of over 70%,

said alloy being in the rolled temper and having an annealed tensile strength of at least 65,000 p.s.i.

2. A copper base alloy consisting essentially of from 1.5 to 3.5% iron, from 0.02 to 0.21% silicon, from 0.01 to 0.15% phosphorus and the balance copper.

3. A copper base alloy consisting essentially of from 1.5 to 3.5% iron, from 0.02 to 0.21% silicon, from 0.03 to 0.20% zinc and the balance copper.

4. A copper base alloy according to claim 3 containing from 0.01 to 0.15% phosphorus.

5. A copper base alloy according to claim 4 having an IACS electrical conductivity of over 70%, being in the cold rolled and annealed temper and having an annealed tensile strength at least 65,000 p.s.i.

6. A copper base alloy according to claim 4 wherein the silicon is present in an amount from 0.03 to 0.20%, the iron is present in an amount from 1.7 to 3.0%, the phosphorus is present in an amount from 0.01 to 0.10% and the zinc is present in an amount from 0.03 to 0.15%.

7. A copper base alloy according to claim 4 wherein the silicon is present in an amount from 0.10 to 0.17% and the iron is present in an amount from 1.8 to 2.9%

References Cited UNITED STATES PATENTS 1,778,668 10/1930 Fuller 75--1'60 2,155,406 4/1939 Crampton et a1 75-1575 3,039,867 6/ 1962 McLain 75-l53 FOREIGN PATENTS 256,457 8/ 1926 Great Britain.

OTHER REFERENCES Transactions of AIME, vol. 188, December 1950, pp.

1486, 1487, 1495 and 1498.

CHARLES N. LOVELL, Primary Examiner US. (:1. X.R. 

